Q&A: A look at the solar plane attempting first round-the-world trip and pioneers behind it

March 10, 2015 2:01 PM

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Described by its creators as "an airborne laboratory," the single-seat Solar Impulse 2 has 17,248 ultra-efficient solar cells that transfer solar energy to four electrical motors that power the plane's propellers. The cells also recharge four lithium polymer batteries to power the plane at night. At around 2,300 kilograms (5,070 pounds), the carbon-fiber Si2 weighs about 2,300 kilograms (5,070 pounds), about as much as a minivan or mid-sized truck. An empty Boeing 747, which has about the same wing span, weighs some 180,000 kilograms (400,000 pounds).

The plane's ideal flight speed is about 25 knots, or 45 kph (28 mph), though that can double during the day when sun's rays are strongest. The plane will reach an altitude of around 28,000 feet (8,500 meters) during the day and at night dip to around 5,000 feet (1,500 meters) when flying over oceans...